Abstract: A power boost system for a portable radiotelephone (10) employs a booster unit (52) to provide sufficient power for operation of the radiotelephone as a mobile unit in a cellular telephone system, and a junction box (54) which, in combination with a mechanical holder (56) allows for hands-free operation of the radiotelephone in the mobile telephone environment. The junction box is provided with a speaker (62) and a microphone (64) to facilitate the hands-free operation. The desired output power level for radiation from a vehicular antenna (72) is provided by a gain-controlled amplifier (80) in response to a pulse-width modulated command signal (48, 90) provided by a computer (12) within the radiotelephone. A memory (70) within the booster unit stores power level data for the higher levels of power to be used during transmission by the booster unit, the power level data being provided to the computer (12) in generating the power command signal.

Abstract: A method for providing a positive transmitter power switch-on in a dual-mode mobile phone is disclosed. According to the invention the transmitter is switched on in two or more phases, controlled by the mobile phone microprocessor program. Preferably the power amplifier sections are switched on in a sequence, so that the output power amplifier sections (3 and 4) are first switched on by enabling the transmit enable signal (TXE). Then the input power amplifier sections (1 and 2) are switched on by enabling ramp-up signal (RAMP-UP) Transmission is thereafter enabled by the transmit power control signal (TXC) being switched on, the amplifiers then output the amplified radio frequency input signal (RFIN) to the duplex circuit (10) transmit terminal (TX).